Prognostic significance of tumor mitotic rate in T2 melanoma staged with sentinel lymphadenectomy.

BACKGROUND AND OBJECTIVES: Tumor mitotic rate (TMR) is an important prognostic variable for patients with thin melanoma. However it remains unclear what the significance of TMR is for more deeply invasive melanoma pathologically staged with a sentinel lymph node biopsy. We sought to determine the prognostic value of TMR in clinically node-negative T2 melanoma patients staged with sentinel lymphadenectomy. METHODS: A prospective IRB-approved database of cutaneous melanoma patients treated from 09/01/1997-03/01/2011 was used to identify patients with T2 melanoma staged with a SLN. Associations were evaluated using Fisher's Exact test, and Kaplan-Meier analysis. RESULTS: Three hundred thirteen T2 patients were included. 19% had ulceration, 11% a positive sentinel node (SLN), and 10% recurred. 44% of patients had TMR ≥ 1/mm(2). TMR ≥ 1/mm(2) did not predict SLN status. TMR ≥ 1/mm(2) was significantly associated with recurrence in SLN negative patients; only 3% of those with TMR < 1/mm(2) developed a recurrence compared to 16% of those with TMR ≥ 1/mm(2) (P < 0.0001). CONCLUSIONS: Although TMR ≥ 1/mm(2) is not associated with risk of SLN involvement in T2 melanoma, it is a significant risk factor for recurrence when SLN negative. As such, TMR could be used to stratify follow-up regimens in SLN negative T2 patients.

Assessment of tumor mitotic rate in primary cutaneous malignant melanomas 1 mm or less in thickness.

BACKGROUND: Tumor mitotic rate in thin melanomas is recognized as a powerful, independent prognostic factor predicting survival. In nonulcerated cases, the presence of any dermal mitotic activity upstages the disease to pT1b. The extent to which tissue should be histologically examined to assess mitogenicity, however, has not been studied. OBJECTIVE: We sought to determine whether in staging thin melanomas, there is a significant benefit in examining numerous tissue sections containing invasive disease. METHOD: In all, 71 cases of thin cutaneous melanomas diagnosed between January 2012 and June 2013 were identified after a search performed on the Pathlab database. The slides were retrieved and reviewed retrospectively, comparing the identification of the first dermal tumor mitotic figure, if present, at 4 check-points: the first, third, fifth, or tenth tissue section examined. RESULTS: A statistically significant difference in identification of the first dermal mitotic figure was found in examining 1 versus 3 tissue sections (P = .0411). No significant difference was found in examining numerous tissue sections. LIMITATIONS: This was a retrospective study from a single institution with a limited number of participants. CONCLUSION: In staging thin melanomas without ulceration, the optimal number of sections to assess is 3. No additional benefit is gained by examining numerous tissue sections.

Clinical significance of tumor mitotic rate and lack of epidermal attachment in melanoma of the head and neck.

BACKGROUND: The primary purpose of this study was to identify the prognostic role of primary dermal melanoma and tumor mitotic rate in melanomas of the head and neck. METHODS: A retrospective review of the histopathologic, clinical, and demographic data of 256 patients was performed to investigate the impact of primary dermal melanoma and tumor mitotic rate on sentinel lymph node positivity, recurrence, and 5-year overall and disease-free survival. RESULTS: Increased tumor mitotic rate, but not primary dermal melanoma, is a significant predictor of sentinel lymph node positivity and higher likelihood of recurrence. Survival analysis demonstrated that both increased tumor mitotic rate and primary dermal melanoma decreased the 5-year overall and disease-free survival rates of patients with head and neck melanoma lesions. CONCLUSION: Tumor mitotic rate and primary dermal melanoma may have prognostic significance for both overall and disease-free survival in patients with head and neck melanoma. A larger prospective study is warranted to further elucidate prognostic factors for melanoma in the head and neck region.